The analytical method and other qualitative research methods to guide the field leakage prevention and plugging lack of pertinence. Meanwhile

the engineering data used by the quantitative prediction method in the prediction of leakage is incomplete and how to control the leakage quantitatively by adjusting the relevant parameters is not proposed after the loss degree is predicted. In or

der to solve the above problems

the cocoon stripping algorithm is proposed. Selecting all measurement parameters of 27 of 29 wells in Shunbei Oilfield with average loss rate recorded

and then taking the average loss rate as the objective function

the well depth and drilling and completion fluid density as the independent variables

the multiple linear regression equation is established

and the undetermined coefficients of the equation are solved. Theoretically

T test and F test are used to prove that the equation can meet the requirements of engineering analysis. In practice

the relative error between the calculated value and the actual value of two wells that did not participate in the equation establishment is about 6 %

proving that the equation meets the needs of engineering control. Finally

17 factors affecting the average loss rate have been screened out by the target equation simplified by the contribution rate method and the cutting element method

among which 10 drilling fluid factors contribute more than 50 %

indicating that a certain average loss rate could be controlled by adjusting the performance of drilling fluid. For the convenience of field control

the performance of drilling fluid is changed by the reading of six-speed viscometer at 300 r/min

so that the main controlling parameters of drilling fluid are reduced to two

which are pH value and the reading of six-speed viscometer at 300 r/min. The minimum average loss is predicted to be 2.3 m

3

/h through the analysis of the three-element equation. Considering the characteristics of Shunbei block

the leakage in Shunbei oilfield involves geological

engineering

and other operation links is found out through quantitative analysis

and so does the main controlling factors of drilling and completion leakage. By means of cutting elements

contribution rate and other methods

the minimum average leakage rate obtained by controlling the funnel viscosity and the reading of six-speed viscometer at 300 r/min is calculated. In the aspect

of guiding the field practice of plugging leakage

it can provide basic data support for the subsequent construction measures to obtain the ideal leak control effect

and provide an optional means for decision-making.