阅读说明：本技术 一种钻井液体系及钻井维护工艺 (Drilling fluid system and drilling maintenance process ) 是由 杨志英 于 2019-09-28 设计创作，主要内容包括：本发明公开一种钻井液体系,所述钻井液配方包括以下物质按重量份配比而成：0.1-0.3％CaO、2-4％HS-1、0.4-0.6％KPAM、0.3-0.5％NW-1、0.5-2％单封(DF-1),以及余量的清水,石灰石粉根据需要量添加；所述钻井液配方还可以是由包括以下物质按重量份配比而成：0.2-0.3％CaO、0.3-0.5％NW-1、2-4％HS-1、0.4-0.6％KPAM、2-4％MFG-1、3-4％超细碳酸钙、以及余量的坂土浆,石灰石粉根据需要量添加；所述超细碳酸钙粒度为1200目。开公开了一种上所述钻井液体系的钻井维护工艺,包括不同井深时添加不同的物质的操作。本发明选取多种钻井液材料,经过多次试验验证重新组合形成了相应的钻井维护施工工艺,能够提高水平井井壁稳定性,解决岩屑携带等水平井钻井难点。(The invention discloses a drilling fluid system, which comprises the following components in parts by weight: 0.1-0.3% of CaO, 2-4% of HS-1, 0.4-0.6% of KPAM, 0.3-0.5% of NW-1, 0.5-2% of single seal (DF-1), and the balance of clear water and limestone powder are added according to the required amount; the formula of the drilling fluid can also be prepared from the following substances in parts by weight: 0.2 to 0.3 percent of CaO, 0.3 to 0.5 percent of NW-1, 2 to 4 percent of HS-1, 0.4 to 0.6 percent of KPAM, 2 to 4 percent of MFG-1, 3 to 4 percent of superfine calcium carbonate and the balance of bentonite slurry, wherein limestone powder is added according to the required amount; the granularity of the superfine calcium carbonate is 1200 meshes. The drilling maintenance process of the drilling fluid system comprises the operation of adding different substances at different well depths. According to the invention, a plurality of drilling fluid materials are selected, and are verified and recombined through a plurality of tests to form a corresponding drilling maintenance construction process, so that the stability of the horizontal well wall can be improved, and the drilling difficulties of the horizontal well such as rock debris carrying and the like are solved.)

1. A drilling fluid system characterized by:

the drilling fluid formula comprises the following substances in parts by weight: 0.1-0.3% of CaO, 2-4% of HS-1, 0.4-0.6% of KPAM, 0.3-0.5% of NW-1, 0.5-2% of single seal (DF-1), and the balance of clear water and limestone powder are added according to the required amount;

the formula of the drilling fluid can also be prepared from the following substances in parts by weight: 0.2 to 0.3 percent of CaO, 0.3 to 0.5 percent of NW-1, 2 to 4 percent of HS-1, 0.4 to 0.6 percent of KPAM, 2 to 4 percent of MFG-1, 3 to 4 percent of superfine calcium carbonate, and the balance of bentonite slurry, and limestone powder is added according to the required amount.

2. A drilling fluid system according to claim 1, wherein: the granularity of the superfine calcium carbonate is 1200 meshes.

3. A process for wellbore servicing of the drilling fluid system of claim 1, wherein: the method comprises the following steps:

s1, normal drilling maintenance is carried out, and the inhibition of the drilling fluid is improved by 0.75-1% KPAM;

s2, before entering a directional section 2500m, adopting 2-4% of HS-1+ cement glue solution, controlling the API water loss within a design range, and simultaneously starting to supplement NW-1;

s3, drilling to 2200m, and extracting the density to 1.10g/cm by using limestone powder³Seepage during drillingSupplementing 0.5-2% DF-1 when leaking;

s4, drilling to 2500m, and carrying out a pressure-bearing leakage-stopping test according to the design;

s5, when directional drilling is started, increasing the molecular viscosity to 60-80 s;

s6, when the well deviation reaches 30 degrees, increasing the mud density to 1.20g/cm³Balancing the formation pressure, timely supplementing the while-drilling plugging agent when increasing the density, wherein the weighting material adopts superfine calcium carbonate or limestone powder;

s7, drilling to 2700m, adding MFG-1 to control the water loss of API within 4ml and the water loss of HTHP within 10 ml.

Technical Field

The invention relates to the technical field of drilling engineering, in particular to a drilling fluid system and a drilling maintenance process.

Background

In recent years, the consumption of oil and gas resources has increased substantially, and in the face of such a rapid increase, oil and gas resources face the risk of depletion, and the exploitation of surface oil and gas has not been able to meet the increasing demand. The problems of borehole wall collapse, hole shrinkage, formation fracturing and the like, borehole wall collapse, hole shrinkage, formation fracturing and the like often occur in the drilling process. Therefore, people are devoted to the research of well wall stabilization technology, and most researchers mainly aim at reducing the adverse effect of the drilling fluid on the stability of the well wall and research a drilling fluid system capable of avoiding the instability of the well wall.

With the continuous deepening of the development of the oil field in the Changqing, the two-opening and three-opening horizontal well, the large-displacement directional well and the windowing sidetracking horizontal well gradually become main means for increasing the yield of the oil field. With the attendant increase in drilling difficulty, conventional drilling fluid systems have failed to meet the above-mentioned drilling needs. The method can improve the stability of the horizontal well wall and solve the problem of carrying rock debris according to the current development situation of the oil field in Changqing, the drilling cost, the stratum characteristics and the domestic construction requirements of the well of the type.

Disclosure of Invention

To solve the above existing problems, the present invention provides a drilling fluid system and a drilling maintenance process. The invention is realized by the following technical scheme.

The drilling fluid system is characterized in that the drilling fluid formula comprises the following substances in parts by weight: 0.1-0.3% of CaO, 2-4% of HS-1, 0.4-0.6% of KPAM, 0.3-0.5% of NW-1, 0.5-2% of single seal (DF-1), and the balance of clear water and limestone powder are added according to the required amount;

the formula of the drilling fluid can also be prepared from the following substances in parts by weight: 0.2 to 0.3 percent of CaO, 0.3 to 0.5 percent of NW-1, 2 to 4 percent of HS-1, 0.4 to 0.6 percent of KPAM, 2 to 4 percent of MFG-1, 3 to 4 percent of superfine calcium carbonate, and the balance of bentonite slurry, and limestone powder is added according to the required amount.

Preferably, the superfine calcium carbonate has a particle size of 1200 meshes.

The drilling maintenance process of the drilling fluid system comprises the following steps:

s1, normal drilling maintenance is carried out, and the inhibition of the drilling fluid is improved by 0.75-1% KPAM.

S2, before the water enters the orientation section 2500m, 2-4% of HS-1+ cement glue solution is adopted, API water loss is controlled within a design range, and NW-1 is supplemented at the same time.

S3, drilling to 2200m, extracting the density to 1.10g/cm3 by using limestone powder, and supplementing 0.5-2% DF-1 when leakage exists during drilling.

And S4, drilling to 2500m, and carrying out a pressure-bearing leakage-stopping test according to the design.

S5, when directional drilling is started, dry increasing the molecular viscosity to 60-80 s.

S6, when the well deviation reaches 30 degrees, the density of the mud is increased to 1.20g/cm3 to balance the formation pressure, and the drilling plugging agent is timely supplemented when the density is increased. The weighting material adopts superfine calcium carbonate or limestone powder.

S7, drilling to 2700m, adding MFG-1 to control the water loss of API within 4ml and the water loss of HTHP within 10 ml.

The invention has the beneficial effects that:

the formula of the drilling fluid system is that the drilling fluid material on the current market is selected, the development status of the Changqing oil field, the drilling cost, the formation characteristics and the construction requirements of domestic wells of the type are fully considered, and a new drilling fluid system formula is finally formed; and multiple tests verify that the recombination forms a corresponding drilling maintenance construction process, the stability of the horizontal well wall can be improved, and the difficulty of horizontal well drilling such as rock debris carrying is solved.

Detailed Description

The technical solution of the present invention will be described in more detail and fully with reference to the following embodiments.